Satellite Internet faster than advertised, but latency still awful

Satellite latency is 638ms, 20 times higher than terrestrial broadband.

The upload and download speeds promised by satellite Internet providers may not be huge, but it turns out that satellite service delivers much better speeds than it advertises.

Satellite's latency has improved too, but unfortunately it's still 20 times worse than non-satellite services.

The Federal Communications Commission today released its latest Measuring Broadband America report, and for the first time it included results on satellite technology alongside cable, DSL, and fiber-to-the-home. ViaSat is the only satellite provider measured. The company's Exede service promises 12Mbps down and 3Mbps up, but in reality it does much better.

The FCC tested speeds at the homes of 6,733 volunteers over the course of a month, in September 2012.

FCC

Satellite merited inclusion in the latest report because newer satellites have greatly expanded the performance of satellite broadband in general. Latency, though, remains satellite's Achilles' heel. The lengthy round trip that data packets have to make between Earth and satellites results in a noticeable delay between the moment a user clicks on something and the moment in which the user sees the result.

This is particularly troublesome for online gaming. The satellite providers themselves admit that satellite is generally only the best option in parts of the country where the other choices are dial-up or slow DSL service. Data caps also reduce the desirability of satellite. If you can get cable or FiOS, that would be the way to go (even if service offered by the major players leaves much to be desired).

"Satellite systems involve the transmission of information over long distances and have correspondingly higher latencies than for terrestrial technologies," the FCC said. "ViaSat had a measured latency of 638ms for this report, approximately 20 times that [of] the terrestrial average."

The average terrestrial service was measured at 29.6 milliseconds latency. Fiber-to-the-home services led the pack. "During the September 2012 testing period, fiber-to-the-home services provided 18ms round-trip latency on average, while cable-based services averaged 26ms, and DSL-based services averaged 44ms. This compares to figures from the April 2012 testing period of 18ms for fiber, 26ms for cable and 43ms for DSL," the FCC said.

Despite that latency problem, the FCC is optimistic about satellite's potential.

Newer, higher-capacity satellites and technological improvements "have decreased latency and improved the quality of satellite broadband service available to subscribers," the FCC said. "While latency for satellites necessarily remains much higher than for terrestrial services, with the improvements afforded by the new technology we find that it will support many types of popular broadband services and applications."

"Beginning in 2011, the consumer broadband satellite industry began launching a new generation of satellites to significantly improve overall performance," the FCC said. "In October of that year ViaSat launched its ViaSat-1 satellite, which has an overall capacity of 140Gbps. In addition to increasing bandwidth capacity, ViaSat and other satellite industry operators have lowered overall latency by making improvements to other elements of their architecture, such as by dispensing with the need to request communication channel assignments, adopting advances in consumer satellite terminal equipment, incorporating protocol acceleration technology, and developing new error correction technology to provide resiliency to rain fade. Despite these many improvements, latency for this new generation [of] satellite-delivered broadband remains high."

With the exception of satellite's addition, nothing too drastic has changed since the last time we covered the FCC's Measuring Broadband research in July 2012. In previous reports, satellite stats were released as part of the raw data but not actually included in the final reports, because the FCC "recognized that the industry was on the verge of a major transition."

Nothing about caps? Was thinking about moving to a place where satellite or dial up would have been my only option for internet a few years ago and was horrified by the almost cellphone like data caps on the way overpriced plans. Wasn't the only reason I didn't move, but it played a part in why I didn't move.

The distance penalty is non-trivial. From ground to space and back to ground is some 72,000 miles for a satellite in equatorial orbit. That's 240 milliseconds.

But that assumes you're standing at the equator. I assume that latency will also be non-trivially impacted by your location, the satellite's location, and the distance between the two. There's also got to be some added latency when you communicate with the target -- if you buy satellite service and try to game on it, it's not like Blizzard has a point-to-point relay with the satellite network. The data still has to be piped over.

(At least, I think that's the case. I could be wrong here).

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

This article doesn't explain the reason for the latency as well as it could. After all if radio waves travel at light speed then the trip time between satellite and ground shouldn't matter much.

Actually, the trip time is a significant portion of the delay. The round trip to the satellite takes about a quarter second, which would already put satellite latency at 10x that of terrestrial services, even before adding other delays.

Having had satellite Internet for 6 years (just recently moving to Verizon HomeFusion [4G LTE]), IMHO data caps are the Achilles' heel -- not latency. If you don't play online games (I don't) then latency is just a pain, whereas data caps of 10-25GB per month are a killer.

Using ViaSat's own tool to determine how much of a data cap I should pay for tells me that if I watch 5 hours of HD, and 10 hours of SD TV per month I will use 19 GB of data. That's only 6 GB under their max data cap of 25 GB -- which costs $130/mo. So 15 hours of streaming PER MONTH for $130. All latency does is cause the video I'm streaming to buffer for a few extra seconds.

HomeFusion is better -- same price and data caps, but much better on latency and speed -- but not much, though I can't complain since I chose to live in the country.

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

Mario Kart isn't twitched based, but would be unplayable at that latency, especially if the jitter is also bad.

FPS's aren't the only games where game objects' position and timing matter. The only games I can think of that would work just fine at such high latency are tic-tac-toe / chess / scrabble. I doubt even Google Docs would present a reasonable experience at that latency if there's a lot of collaboration going on that's dependent on others' real-time typing.

This article doesn't explain the reason for the latency as well as it could. After all if radio waves travel at light speed then the trip time between satellite and ground shouldn't matter much.

If the satellites are in geosynchronous orbit then its about a 70,000 km round trip. Dividing by the speed of light, we get a minimum latency of 233 ms.

And depending on the protocol used (TCP as an example) you may have to double that time because the packets have to have acknowledged before more are sent which can effectively double your latency. I realize this is also an issue with any other internet connection, but with satellite it can make the latency feel much worse than what you would mesure it being for a single packet.

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

Mario Kart isn't twitched based, but would be unplayable at that latency, especially if the jitter is also bad.

FPS's aren't the only games where game objects' position and timing matter. The only games I can think of that would work just fine at such high latency are tic-tac-toe / chess / scrabble. I doubt even Google Docs would present a reasonable experience at that latency if there's a lot of collaboration going on that's dependent on others' real-time typing.

A number of Facebook games would work at that latency, no problem. So would turn-based strategy games. RTS's would lag significantly, but some might be playable depending on speed and how well the network code is tuned for high latency.

I'm not saying it'd be ideal. And there are a lot of games that wouldn't play well. But there are still titles that would.

This article doesn't explain the reason for the latency as well as it could. After all if radio waves travel at light speed then the trip time between satellite and ground shouldn't matter much.

If the satellites are in geosynchronous orbit then its about a 70,000 km round trip. Dividing by the speed of light, we get a minimum latency of 233 ms.

And depending on the protocol used (TCP as an example) you may have to double that time because the packets have to have acknowledged before more are sent which can effectively double your latency. I realize this is also an issue with any other internet connection, but with satellite it can make the latency feel much worse than what you would mesure it being for a single packet.

The distance penalty is non-trivial. From ground to space and back to ground is some 72,000 miles for a satellite in equatorial orbit. That's 240 milliseconds.

But that assumes you're standing at the equator. I assume that latency will also be non-trivially impacted by your location, the satellite's location, and the distance between the two. There's also got to be some added latency when you communicate with the target -- if you buy satellite service and try to game on it, it's not like Blizzard has a point-to-point relay with the satellite network. The data still has to be piped over.

(At least, I think that's the case. I could be wrong here).

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

That's one way latency; but for browsing, etc you'll always have twice that. >240ms to send the request from your computer to the web server, and >240ms to send it back from the server to your computer. Assuming that's the latency being measured this is about as good as it's going to get for Geo satellites.

You need dozens of satellites to get continuous coverage: ex Iridium has 66 active satellites + several in orbit spares.

Because the satellites aren't in a fixed location relative to you, you either need to use omnidirectional or wide beam antennas (wide enough that there's always at least one sat in the beam), or antennas that track the satellites as the orbit; to avoid interruption of service when switching because the current sat is moving too far away you'd need at least two antennas.

Since the satellites you'd be contacting are moving you'd need a larger amount of clear line of sight. In built up or wooded areas this might not be possible.

My parents had Hughes. It was OK as long as you really limited your daily usage. The 250mb DAILY limit was frustrating at best. Nothing like paying high prices for worse than dial-up speeds. When the whole family would get together the 250 would go fast.

"We've been FAPPED! Who was using Youtube again?!?!" "Oh, I saw that you needed the latest windows service pack.... oh, oops.""Oh, I was only playing Farmville."

Once you have had broadband for awhile you just don't think twice about downloading big things. My brother-in-law would make a daily pilgrimage into town to the McDonalds for the free wi-fi so he could catch up on his email.

It would be interesting to try to bond Satellite and POTS 56K dialup. For low bandwidth stuff (user clicks, packet acknowledgements, email text), it goes across copper wires. When transferring large amounts of data, it goes by Satellite.

I remember playing Diablo2 multiplayer on 56K with basically no lag problems (unless a zookeeper joined - you know who you are).

It would be interesting to try to bond Satellite and POTS 56K dialup. For low bandwidth stuff (user clicks, packet acknowledgements, email text), it goes across copper wires. When transferring large amounts of data, it goes by Satellite.

I remember playing Diablo2 multiplayer on 56K with basically no lag problems (unless a zookeeper joined - you know who you are).

Certainly non-trivial, but in the USA, everyone has POTS.

That was the old way of doing satellite was kind of like that. Everything up went over POTS and down was through the dish. It was awful. You would also be amazed at the number of homes without POTS. Either the family is using just cell phones or they cut the wires and have VOIP in the house. Cut ours 10years ago and never looked back. I got something from AT&T in the mail about going back to POTS and what a discount I was going to get on long distance. I had to laugh. People still pay for long distance?

The distance penalty is non-trivial. From ground to space and back to ground is some 72,000 miles for a satellite in equatorial orbit. That's 240 milliseconds.

But that assumes you're standing at the equator. I assume that latency will also be non-trivially impacted by your location, the satellite's location, and the distance between the two. There's also got to be some added latency when you communicate with the target -- if you buy satellite service and try to game on it, it's not like Blizzard has a point-to-point relay with the satellite network. The data still has to be piped over.

(At least, I think that's the case. I could be wrong here).

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

actually, it sounds like just the opposite - distance (to the satellite) doesn't really matter...

The current LEO constellations of Globalstar and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude.

The proposed O3b Networks MEO constellation scheduled for deployment in 2013 would orbit at 8,062 km, with RTT latency of approximately 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s (Gigabits per second).

The planned COMMStellation™, scheduled for launch in 2015, will orbit the earth at 1,000 km with a latency of approximately 7 ms. This polar orbiting constellation of 78 microsatellites will provide global backhaul with throughput in excess of 1.2 Gbit/s.

The satellite providers themselves admit that satellite is generally only the best option in parts of the country where the other choices are dial-up or slow DSL service.

I don't see a scenario where a satellite service would outperform DSL. I'd take 512Kbit DSL over satellite any day of the week.

Yes, you get higher nominal speeds, but you can't use them for downloading big stuff, since you'll hit your caps very quickly. But for basic browsing, the horrid latency is much more of an issue than the bandwidth itself.

Remeber that the satellite is not the source of the data, it's just a router along the path, so each packet, in each direction, needs to make the trip twice (once up, once down).

So, the measured latency includes 4 trips across the distance.

Between Australia and Zambia we managed to get the latency down to 550ms across satellite , in a desperate attempt to get decent terminal services performance. It was usable, if barely.

You could reduce the latency be nearly half if you use a different connection mechanism for outgoing packets - in the old days we used to use dial-up for the uplink, although admittedly because the dish was downlink only.

But this is just one provider (and not a well known one at that). Just because this service provides data speeds faster than advertized doesn't mean the other ones do. Shouldn't 2 satellite companies whose names start with a "D" have also been tested?

The distance penalty is non-trivial. From ground to space and back to ground is some 72,000 miles for a satellite in equatorial orbit. That's 240 milliseconds.

But that assumes you're standing at the equator. I assume that latency will also be non-trivially impacted by your location, the satellite's location, and the distance between the two. There's also got to be some added latency when you communicate with the target -- if you buy satellite service and try to game on it, it's not like Blizzard has a point-to-point relay with the satellite network. The data still has to be piped over.

(At least, I think that's the case. I could be wrong here).

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

actually, it sounds like just the opposite - distance (to the satellite) doesn't really matter...

The current LEO constellations of Globalstar and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude.

The proposed O3b Networks MEO constellation scheduled for deployment in 2013 would orbit at 8,062 km, with RTT latency of approximately 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s (Gigabits per second).

The planned COMMStellation™, scheduled for launch in 2015, will orbit the earth at 1,000 km with a latency of approximately 7 ms. This polar orbiting constellation of 78 microsatellites will provide global backhaul with throughput in excess of 1.2 Gbit/s.

Your conclusion that distance doesn't matter is the opposite of what the data you pulled it showing. Those are all low/mid earth orbit constellations which are much closer to the ground than the higher speed GEO satellites and are much lower latency as a result.

The RTT being quoted appears to be the time for a signal to go from ground-sat-ground (web page latency is a minimum of twice that). The Speed of light contributes to 9 ms for Globalstar, 4ms for Iridium, 53ms for O3b, and 6.6ms for COMMStellation.

Assuming they reach their target performance numbers, COMMStellation is due praise for almost completely eliminating routing latency on the satellites themselves. GlobalStar/Irridium aren't that bad for latency either; unless O3b is high enough up and spread out enough that straight up isn't a valid approximation for speed of light lag (it's not for GEO at temperate latitudes) they appear to have a badly laggy onboard design.

But this is just one provider (and not a well known one at that). Just because this service provides data speeds faster than advertized doesn't mean the other ones do. Shouldn't 2 satellite companies whose names start with a "D" have also been tested?

Presumably the last generation constellations were considered as hopelessly obsolete/failtastic and ignored just like ISDN "broadband" is. ViaSat is operating one of the first of the new generation of GEO sats to be deployed.

The distance penalty is non-trivial. From ground to space and back to ground is some 72,000 miles for a satellite in equatorial orbit. That's 240 milliseconds.

But that assumes you're standing at the equator. I assume that latency will also be non-trivially impacted by your location, the satellite's location, and the distance between the two. There's also got to be some added latency when you communicate with the target -- if you buy satellite service and try to game on it, it's not like Blizzard has a point-to-point relay with the satellite network. The data still has to be piped over.

(At least, I think that's the case. I could be wrong here).

I'm guessing 300-400ms is probably the best real-world case you could hope for with satellite. And that's fine for lots of things, including online gaming that isn't so twitch-based.

actually, it sounds like just the opposite - distance (to the satellite) doesn't really matter...

The current LEO constellations of Globalstar and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude.

The proposed O3b Networks MEO constellation scheduled for deployment in 2013 would orbit at 8,062 km, with RTT latency of approximately 125 ms. The proposed new network is also designed for much higher throughput with links well in excess of 1 Gbit/s (Gigabits per second).

The planned COMMStellation™, scheduled for launch in 2015, will orbit the earth at 1,000 km with a latency of approximately 7 ms. This polar orbiting constellation of 78 microsatellites will provide global backhaul with throughput in excess of 1.2 Gbit/s.

There's an important tradeoff here, though. You're losing the fixed link setup a GEO bird has (like you have on a home connection) with a setup more like a cellular link. The antenna for an LEO link can't be a precise unit like the parabolic. That 1.2Gbit/s number is the backhaul, which means the total available bandwidth for all users. That type of network is more for setting up a small, short-term connection than a constant-on system.

The current LEO constellations of Globalstar and Iridium satellites have delays of less than 40 ms round trip, but their throughput is less than broadband at 64 kbit/s per channel. The Globalstar constellation orbits 1,420 km above the earth and Iridium orbits at 670 km altitude.

You need a very focused dish to communicate with a geostationary orbit satellite. One advantage is that you then get the whole Ka and Ku frequency spectrum for your own use. You can even combine linear and circular polarizations. Futhermore, with Ka spotbeams, the satellite operator can increase the throughput even more.

To communicate with lower earth orbit satellites, you don't need focused antennas, so they are more useful for mobile applications. Consequently the frequency spectrum is shared with other applications from other directions - that's why the lower speeds.

When I was on Dial up I only had 300 to 500ms latencys! Throw in the awful data caps, to make satellite the internet of last resort.

300-500ms to what, the opposite side of the planet? I know at least for things on the same side of the country as I was in the mid-90s, I got more like 150-200ms on a good day. I didn't really pay as much attention earlier than that because I hadn't started mudding yet, but that was plenty quick enough for that. Heh.

We aren't just pinging to the satellite and back. Every packet is going up and down at least twice—four ground-orbit transmissions—and bouncing all over the Internet in between.

Could you decrease latency if both ends used the same satellite? For example, if you needed to connect remote locations with your central office?

Then this in effect becomes intra-satellite routing, without the need to go to the public internet.

It's possible, and it's done in mesh systems like Iridium, but I'm curious myself whether Viasat (or DirecPC) actually have the routing capacity in the satellite to do this, or if everything is bridged blindly back to the terrestrial base.

I know all the airplane wifi I've used so far has had DirecPC uplinks... Anyone on a flight in the next few months want to try a flight-to-flight traceroute?

Like it or not, satellite is the only option in some places. Since it does not depend on any type of terrestrial lines, is mainly works anywhere where that satellite has coverage.

Boats, mountains, places far away from civilization, well lets assume you are rich and you have your own private island, satellite would be your only option.

Its exactly on those places, far remote from cities where people appreciate more the Internet and communication which lets them keep a close contact to the rest. Imagine having a satellite connection in a remote island, Internet is probably the only thing that will keep you there.

I don´t think latency will be ever solved in satellites, its just how they work. I think software, games, servers, etc, should be prepared and developed for high latency scenarios. Even without satellites its funny how games and applications assumes everyone has a great latency. Even with terrestrial connections this does is the case as a norm.

I think a standard of 500 ms should the norm for as high as it gets. 500 ms is pretty awful for today's standards, but very much possible for almost everywhere. Sadly I don´t think even satellites hit that range yet based on this article.

If we think about it 1000ms is nothing more than a second. 1 second of your life should have that dramatic effect on you consume content, but it seems most software, voip, etc, almost everything will not work properly with 1 second delay. They don´t buffer enough or just assume everyone has great a great latency and decide it will not work for that small % of users that rely on high latency.

So I think 500 ms is more realistic. Scientist, military operations, remote places, far away on sea, there are allot of situations where you will still rely on satellite internet as your only option. I just hope satellite improves with time and gets better.